[Federal Register: July 6, 2005 (Volume 70, Number 128)]
[Proposed Rules]
[Page 38849-38861]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06jy05-37]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
Endangered and Threatened Wildlife and Plants; 90-Day Finding on
a Petition To List the American Eel as Threatened or Endangered
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Notice of petition finding and initiation of status review.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a
90-day administrative finding on a petition to list the American eel
(Anguilla rostrata) under the Endangered Species Act of 1973, as
amended (Act). We find the petition presents substantial information
indicating that listing the American eel may be warranted. We are
initiating a status review to determine if listing the species is
warranted. To ensure that the review is comprehensive, we are
soliciting information and data regarding this species.
DATES: The administrative finding announced in this document was made
on July 6, 2005. To be considered in the 12-month finding for this
petition, data, information, and comments should be submitted to us by
September 6, 2005.
ADDRESSES: Data, comments, information, or questions concerning this
petition should be sent to Martin Miller, Chief, Division of Endangered
Species, Region 5, U.S. Fish and Wildlife Service, 300 Westgate Center
Drive, Hadley, MA 01035-9589; by facsimile to 413-253-8428; or by
electronic mail to AmericanEel@fws.gov. The petition finding,
supporting information, and comments are available for public
inspection, by appointment, during normal business hours at the above
address.
[[Page 38850]]
FOR FURTHER INFORMATION CONTACT: Heather Bell, at the above address
(telephone 413-253-8645; facsimile 413-253-8428). Persons who use a
telecommunications device for the deaf (TDD) may call the Federal
Information Relay Service (FIRS) at 800-877-8339, 24 hours a day, 7
days a week.
SUPPLEMENTARY INFORMATION:
Background
Section 4(b)(3)(A) of the Act requires that we make a finding on
whether a petition to list, delist, or reclassify a species presents
substantial information to indicate that the petitioned action may be
warranted. To the maximum extent practicable, this finding is to be
made within 90 days of receipt of the petition, and the finding is to
be published promptly in the Federal Register.
This finding summarizes information included in the petition and
information available to us at the time of the petition review. Our
review of a 90-day finding under section 4(b)(3)(A) of the Act and
section 424.14(b) of our regulations is limited to a determination of
whether the information in the petition meets the ``substantial
information'' threshold. Our standard for substantial information with
regard to a 90-day listing petition finding is ``that amount of
information that would lead a reasonable person to believe that the
measure proposed in the petition may be warranted'' (50 CFR 424.14(b)).
We have to satisfy the Act's requirement that we use the best
available science to make our decisions. However, we do not conduct
additional research at this point, nor do we subject the petition to
rigorous critical review. Rather, at the 90-day finding stage, we
accept the petitioner's sources and characterizations of the
information, to the extent that they appear to be based on accepted
scientific principles (such as citing published and peer reviewed
articles, or studies done in accordance with valid methodologies),
unless we have specific information to the contrary. Our finding
considers whether the petition states a reasonable case for listing on
its face. Thus, our 90-day finding expresses no view as to the ultimate
issue of whether the species should be listed.
On November 18, 2004, the Service and the National Oceanic and
Atmospheric Administration (NOAA Fisheries) received a petition, dated
November 12, 2004, from Timothy A. Watts and Douglas H. Watts,
requesting that the Service and NOAA Fisheries list the American eel as
an endangered species under the Act. The petition contained detailed
information on the natural history of the American eel, its cultural
use, population status, and existing threats to the species. Threats
discussed in the petition included destruction and modification of
habitat, overutilization, inadequacy of existing regulatory mechanisms,
and other natural and manmade factors such as contaminants and
hydroelectric turbines. The petition did not address potential threats
caused by disease or predation. In response to the petitioners' request
to list the American eel, the Service, as administrative lead for the
species, sent a letter to the petitioners dated December 13, 2004,
explaining that the Service, in coordination with NOAA Fisheries, would
review the petition and determine whether or not the petition presents
substantial information indicating that listing the American eel may be
warranted. Jurisdiction for the American eel is jointly held by the
Service and NOAA Fisheries, with the Service having administrative lead
for processing this petition and working closely with NOAA Fisheries
during the process.
Accompanying the petition, and incorporated by reference into the
petition, is the Atlantic States Marine Fisheries Commission's (ASMFC)
Interstate Fishery Management Plan for American Eel (2000). The ASMFC
is an Interstate Compact of the 15 Atlantic Coast States (Maine to
Florida) charged with managing interstate fisheries resources of the
Atlantic Coast. The Compact was approved by the Congress of the United
States in 1942 in Public Law 77-539, and authority was further amended
by Public Law 81-721 and the Atlantic Coastal Fisheries Cooperative
Management Act (Pub. L. 103-206). The Interstate Fishery Management
Plan for the American eel (Management Plan) was developed by ASMFC in
response to declining stocks of American eel and had input from the
public and commercial fishing industry, as well as considerable
technical scrutiny from the scientific community. The Service and NOAA
Fisheries were involved in producing the Management Plan for the
American eel, as representatives to the ASMFC Eel Technical Committee
charged with developing the Management Plan. State agencies and an
academic institution were also involved in developing this document,
and it was approved by the ASMFC board that consists of representatives
from the 15 Atlantic Coast States.
The Management Plan provides a detailed description of the life
history, habitat requirements, the commercial fishery, population
status, and threats to the American eel. The goals of the Management
Plan are to protect and enhance the abundance of American eels in both
inland and territorial waters within ASMFC's jurisdiction, and to
provide for sustainable commercial, subsistence, and recreational
fisheries by preventing overharvest of any eel life stage.
For this finding, the Service utilized the petition and the
Management Plan, which was incorporated into the petition by reference,
and other petition appendices and references. Because of the rigor and
integrity of the Management Plan, and the significance to the American
eel of the geographic area covered by the Management Plan (the Gulf
Stream transports the majority of larval American eel to the Atlantic
Coast States), the Service relied on the petition and Management Plan
in determining that the petitioned action may be warranted.
The ASMFC announced in March of 2004 that it is developing an
amendment to the Management Plan to address continued stock declines.
As part of the amendment process it committed to conduct a benchmark
stock assessment in 2005, and requested that the Service and NOAA
Fisheries conduct a status review of the American eel. Per this
request, the Service agreed in September 2004, prior to receiving the
petition, to conduct a rangewide status review of the American eel in
coordination with NOAA Fisheries and the ASMFC.
Species Information
American eel are a migratory fish species with multiple life stages
that migrate from freshwater to the ocean to spawn (a life history
strategy known as ``catadromy''). American eels require various
habitats over their long-lifespan, including open oceans, large coastal
tributaries, small freshwater streams, and lakes and ponds. They are
opportunistic feeders at every level of the food chain. The North
Atlantic is home to two recognized species of catadromous eel: the
American eel and the European eel (A. anguilla). The range of the
American eel includes western Atlantic drainages from Greenland to
northern portions of South America, including most Caribbean Islands,
the eastern Gulf of Mexico, and inland areas of the Mississippi River
and the Great Lakes drainages. The majority of the American eel
population is along the Atlantic seaboard of the United States. There
is U.S. and international commercial harvest, limited subsistence use
by Native Americans, and limited recreational interest in the American
eel fishery.
[[Page 38851]]
Life History Characteristics
Reproduction and Growth
American eel eggs hatch in the Sargasso Sea, in the western
Atlantic Ocean (for further description of the Sargasso Sea, see
Habitat section below). The required environmental conditions for
reproduction and the incubation period for the American eel are unknown
(ASMFC 2000). The resulting larvae (leptocephali) drift in the upper
300 meters of the Gulf Stream for up to one year before reaching the
North American continent (Kleckner and McCleave 1985, as in ASMFC
2000). At sea, perhaps at the edge of the continental shelf (Hardy
1978, as in ASMFC), the shape of the larvae dramatically changes as
they metamorphose into miniature transparent glass eels (ASMFC 2000).
American eel larvae may only be capable of undergoing metamorphosis
during a specific window beginning after 6-8 months and remain capable
for only 4-6 additional months (McCleave 1987, 1993, as in Castonguay
et al. 1994b).
Glass eels actively migrate toward freshwater and ascend rivers
during the winter and spring by drifting on flooding tides, holding
position near the bottom on ebb tides, and actively swimming along the
shore in estuaries above tidal influence (Facey and Van Den Avyle 1987;
Barbin and Krueger 1994, as in ASMFC 2000). Migration to freshwater
occurs earlier in the southern portion of the range and later in the
northern portion (Helfman et al. 1984, McCleave and Kleckner 1982, as
in ASMFC 2000), possibly due to the increased distance of northern
areas from the Sargasso Sea.
Anadromous fish (e.g., salmon and shad) spawn in freshwater but
spend most of their lives at sea. As they mature, these fish usually
return to their river of origin to repeat the cycle. Return rates and
abundance are driven by prior spawning success, at sea survival, and
environmental conditions. American eels are also highly migratory, but
in the opposite direction. Adult eels migrate from freshwater to the
ocean to spawn (catadromy). Since they are not returning to a home
river, dispersion of juvenile ``glass'' eels back into freshwater is
more likely dependant on environmental conditions, such as ocean and
nearshore currents, river discharge rates, and temperature, as well as
timing of larval metamorphosis (R. StPierre pers. comm. 2005).
Glass eels become elvers when they ascend into brackish or fresh
water and become pigmented (McCleave and Kleckner 1982, as in ASMFC
2000). Upstream migration may occur from May through October (Richkus
and Whalen 1999, as in ASMFC 2000), peaking earlier in the southern and
later in the northern portion of the range (Helfman et al. 1984,
McCleave and Kleckner 1982, as in ASMFC 2000).
Elvers become yellow eels approximately 2 years after hatching and
resemble the adult form. Yellow eels are usually yellow or green, and
reach sizes up to about 11 in (28.0 cm) for males and 18 in (46 cm) for
females (Hardy 1978, as in ASMFC 2000). The timing and duration of
upstream migration is watershed specific, and upstream migration may
occur in most months of the year (ASMFC 2000). The growth rates of
yellow eels are variable, depending on latitudinal location (eels grow
more slowly in the north than in the south) and habitat productivity
(eels grow more slowly in freshwater than in estuarine areas because of
the lack of productivity or nutrients in freshwater as compared to
estuaries) (Richkus and Whalen 1999, as in ASMFC 2000).
The silver eel life stage, during which eels become sexually mature
and begin their spawning migration, begins after 3, and up to 24 years
as a yellow eel. Yellow eels, responding to some environmental or
metabolic signal, begin to migrate downstream in the late summer or
fall. As they proceed downstream, they transform into silver eels
(Hardy 1978; Fahay 1978; Wenner 1973; Facey and Van Den Avyle 1987, as
in ASMFC 2000). This transformation includes several physiological
changes, including: (1) Silvering of the skin; (2) body fattening; (3)
skin thickening; (4) eye enlargement and pigment change; (5) increased
length of capillaries in the rete (a netlike structure) of the swim
bladder; and (6) digestive tract degeneration (Facey and Van Den Avyle
1987).
Sex Ratio. There are several environmental variables that may
influence age at sexual maturity, sexual determination, and the
resulting ratios of females and males (juveniles are not sexually
determined and at a certain stage may be hermaphroditic--being both
sexes). In general, sexual differentiation does not occur until eels
are about 8-10 in (20-25 cm) long (Dolan and Power 1977, as in Facey
and Van Den Avyle 1987). Sexual maturity appears to occur at older ages
and larger sizes in the northern portion of their range when compared
with the southern portion, resulting in northern females being the most
fecund and having a relatively long life span (Helfman et al. 1987, as
in ASMFC 2000). Most sexually mature males are greater than 11 in (28
cm), and older than 3 years of age in the northern populations.
Information from the northern stocks indicates that most sexually
mature females are greater than 18 in (46 cm), and older than 4 years
of age (Hardy 1978, Fahay 1978, as in ASMFC 2000).
It has been hypothesized that sex determination, and the resulting
differences in ratios and distribution, may be due to a variety of
factors, including: (1) Latitudinal differences (females more abundant
in northern areas: McCleave 1996, as in ASMFC 2000), (2) differences in
salinity (females more abundant in freshwater: Facey and LaBar 1981, as
in ASMFC 2000), (3) density dependency (more females in areas of low
density: Fahay 1978, as in Facey and Van Den Avyle 1987), (4) timing
(males returning to spawn earlier than females, and therefore finding
it beneficial to stay in southern latitudes), or (5) energy use (slower
growth, such as that which would occur in typically less productive
areas of northern or inland areas, leads to larger size, and for
females a higher fecundity: Helfman et al. 1987, as in ASMFC 2000).
Spawning. American eel fecundity can range between 0.5 to 21.9
million eggs per female and can be predicted based on female size
(Facey and Van Den Avyle 1987, McCleave and Oliveira 1998, as in ASMFC
2000). High fecundity of the eel is consistent with an r-selected
strategy that assumes high mortality of larval and subadult stages
(Wenner and Musick 1974, Barbin and McCleave 1997, as in ASMFC 2000).
Adult American eels from throughout their range are believed to
synchronize their arrival at the spawning grounds; however, little is
known about the oceanic portion of the spawning migration, or
mechanisms for locating the spawning grounds (Miles 1968, as in ASMFC
2000). The American eel may use the geoelectrical fields generated by
ocean currents for orientation (Rommel and Stasko 1973, as in ASMFC
2000). The depth at which American eels migrate in the ocean has been
hypothesized to vary with light intensity and turbidity (Edel 1976, as
in ASMFC 2000). Migration has been suggested to occur within the upper
few hundred meters of the water column (Kleckner et al. 1983, McCleave
and Kleckner 1985, as in ASMFC 2000). However, Robins et al. (1979, as
in ASMFC 2000) photographed two Anguillid eels, possibly pre-spawning
American eels, at depths of about 6,500 ft (2,000 m) on the floor of
the Atlantic Ocean in the Bahamas.
Some feature of the surface water mass of the Sargasso Sea, such as
thermal fronts, may serve as a cue for
[[Page 38852]]
adult American eels to cease migration and begin spawning. Eels are
thought to spawn in the winter and early spring in the upper few
hundred meters of the water column of the Sargasso Sea (Kleckner et al.
1983, McCleave and Kleckner 1985, as in ASMFC 2000). After spawning,
the spent eel is assumed to die (Facey and Van Den Avyle 1987).
The American eel and the European eel, considered separate species,
both spawn in the Sargasso Sea, but a mechanism for separation,
possibly location, depth, or timing of spawning, is unknown, and an
area of overlap in spawning habitat is likely. Leptocephali of both
species have been captured in the same trawl (McCleave et al. 1986b, as
in Facey and Van Den Avyle 1987). Morphologically, the adult American
and European eel differ in the number of vertebrae or myomeres. Larvae
with the ``American'' and ``European'' myomere counts have partially
separate but overlapping spatial and temporal distributions in the
Sargasso Sea (Schmidt 1922, Schoth 1982, Schoth and Tesch 1982,
Bo[euml]atius and Harding 1985a, b, Mcleave et al. 1987, Kleckner and
McCleave 1988, as in Avise 2003), indicating that spawning areas
overlap to some degree. Both mitochondrial and nuclear gene evidence
show that American and European eels belong to two largely separate
gene pools (Avise 2003). Genetic data in conjunction with vertebral
counts indicate that about 2 to 4 percent of the Icelandic eel are of
American eel ancestry but do not appear to be strays, indicating a zone
of hybridization between the two species (Avise 2003).
Genetic studies indicate that American eels are a single panmictic
breeding population (Williams and Koehn 1984, as in ASMFC 2000),
meaning that it is a single breeding population exhibiting random
mating, and that offspring from any parents are capable of inhabiting
any suitable habitat in any portion of the range. Recent analyses,
however, may indicate genetic variation with latitude, suggesting that
mating within the species is not panmictic in the strict sense and that
dispersal of larvae is not entirely random with respect to where their
parents resided in continental waters (Avise 2003).
Feeding Habits
American eels are carnivorous, and at various life stages and
locations they feed on multiple trophic levels, such as zooplankton and
phytoplankton as leptocephali, aquatic invertebrates as juveniles, and
fish and crustaceans as adults (McCord 1977, Ogden 1970, Wenner and
Musick 1975, as in ASMFC 2000).
Range, Distribution, and Habitat
The American eel occupies fresh, brackish, and coastal waters along
the Atlantic Ocean from the southern tip of Greenland to northeastern
South America, the inland waters near the Caribbean, the eastern Gulf
of Mexico, and inland to the Mississippi River and Great Lakes
drainages. Important aspects of American eel life history, including
spawning, larval development, and migration, occur in the open ocean.
Successful migration of leptocephali (and thus recruitment) depends on
oceanic conditions being suitable to transport the larvae to
continental areas during the window of metamorphosis from larvae into
glass eel on the Continental Shelf (see the Reproduction and Growth
section of this document). The mean circulation in the vicinity of the
spawning area tends to transport larvae westward, and eventually into
the Gulf Stream system, which carries them north and east along the
coast of North America (i.e. Florida to Canada) (McCleave 1993, as in
Castonguay et al. 1994). Other currents may transport larvae in smaller
numbers to the more southerly areas of the range, but the conditions
under which this happens are unclear.
Elver habitat likely includes soft, undisturbed bottom sediments
(Facey and Van Den Avyle 1987) and river currents appropriate for
upstream migration (Tesch 1977; Sorensen 1986; Sorensen and Bianchini
1986, as in ASMFC 2000). Feeding and growth of yellow eels occur in
estuaries and fresh waters over a period of many years (including
offshore, midwater, and bottom areas of lakes, estuaries, and large
streams) (Adams and Hankinson 1928, Facey and LaBar 1981, GLFC 1996,
Helfman et al. 1983, NYSDEC 1997a & b, as in ASMFC 2000; Facey and Van
Den Avyle 1987).
When American eels metamorphose into silver eels and migrate
seaward to their spawning ground, they travel downstream mostly at
night (Bigelow and Schroeder 1953, as in ASMFC 2000) and may inhabit a
broad range of depths throughout the water column.
As mentioned earlier, spawning occurs in the Sargasso Sea, an oval
area in the middle of the Atlantic Ocean, between the West Indies and
the Azores (between 20[deg] to 35[deg] North Latitude and 30[deg] to
70[deg] West Longitude), composed of a nearly 5.2 million km
2 area. Although the boundaries are not easily delineated,
the Sea is identified as the ``eye'' of a large, slow, clockwise moving
gyre of clear, deep blue colored, warm surface waters, with elevated
salinity and low plankton production. The Gulf Stream provides the
western boundary, which along with other ocean gyres (large circular
currents in all the ocean basins), such as the North Equatorial
Current, encircles the Sargasso Sea.
Knowledge of the specific spawning area for the American eel within
the Sargasso Sea is based on the distribution of the smallest
leptocephali, as adults have never been observed in the area. Miller
(1995, as in ASMFC 2000) reported two major distribution patterns for
leptocephali with the highest abundance in areas located near fronts in
the west of the Subtropical Convergence Zone (STCZ) in the southwestern
Atlantic. The smallest leptocephali were reported to have been
collected near the Bahama Banks (the Bahamas) in the Florida Current
and at stations close to the southerly fronts in the western STCZ.
Population Status
Historically, American eels were abundant in East Coast streams and
estuaries, and thought to comprise more than 25 percent of the total
fish biomass (Smith and Saunders 1955, Ogden 1970, as in ASMFC 2000).
Although this species declined from the historic levels, the population
remained relatively stable, some thought, until the 1970s (ASMFC 2000).
Others, including the Southeastern Fishes Council Technical Advisory
Committee, concluded, based on a review of 51 major drainages of the
southern United States, that the regional stock of the American eel was
stable (Warren et al. 2000) through the 1990s, and NatureServe, which
utilizes occurrence data, listed many eel stocks in Atlantic States as
stable in 2001 (NatureServe 2004).
According to the ASMFC (2000), the eel has lost much of its habitat
along the eastern United States. As stated in the petition, the ASMFC
states: ``By region, the potential habitat loss [for American eel] is
greatest (91 percent) in North Atlantic region (Maine to Connecticut)
where stream access is estimated to have been reduced from 111,482
kilometers to 10,349 kilometers of stream length. Stream habitat in the
Mid Atlantic region (New York through Virginia) is estimated to have
been reduced from 199,312 km to 24,534 km of unobstructed stream length
(88 percent loss). The stream habitat in the South Atlantic region
(North Carolina to Florida) is estimated to have decreased from 246,007
km to 55,872 km of unobstructed stream access, a 77 percent loss.''
[[Page 38853]]
Decreases have been noted in the commercial and recreational
fisheries. Since the fisheries' peak in the mid 1970s at 3.5 million
pounds, commercial landings have declined significantly to a near
record low of 868,215 pounds in 2001. Recreational data concerning eel
harvest also appears to indicate a decline in abundance. According to
the National Marine Fisheries Service (now NOAA Fisheries) Marine
Recreational Fisheries Statistics Survey, recreational harvest in 2001
was 10,805 eels, a significant decrease from the peak of 106,968 eels
in 1982 (ASMFC 2000). Harvest data are often all that is available;
however, taken alone without a measure of fishing effort, this type of
data are not good indicators of eel abundance because harvest is
dependent on demand, which can fluctuate dramatically (the number of
commercial harvest permits issued per state can provide a surrogate for
fishing effort, and understanding and adjusting for market fluctuations
can provide a clearer picture of trends). Additionally, changes in
year-class strength are not readily recognizable because most samples
of eels include individuals of similar sizes, but from unknown year
classes, and harvest of young yellow-phase eels for use as crab bait
and as live bait for recreational fisheries frequently go unreported
(Haro et al. 2000).
Richkus and Whalen (1999, as in ASMFC 2000) concluded that there is
broad-based evidence for a decline of American eels from 1984 to 1995
based on a Mann-Kendall trend analysis of eel abundance time series on
eel migration data, including data from the Moses-Saunders eel ladder.
Their results indicate significant negative trends for yellow and/or
silver eel abundance in Ontario, Quebec, New York, and Virginia. The
authors found no trends for glass eel or elvers, but those data sets
were generally not complete and may not have covered the years where
the largest declines were observed in other data sets.
In Canada, different areas report seemingly opposing harvest data.
Commercial landings in the Nova Scotia region of the Gulf of St.
Lawrence and from Newfoundland show variability in yellow and silver
eel landings, but no clear trend. By contrast, an upward trend is
apparent in catches south of the Gulf of St. Lawrence, in the Canadian
Atlantic/Bay of Fundy regions (threefold increase since the mid or late
1980s) (ICES 2000). According to Ontario's Ministry of Natural
Resources, Lake Ontario, which had as many as 10 million eels two
decades ago, now holds only tens of thousands. Ontario's commercial eel
harvest peaked at more than 500,000 lbs (250 tn) in 1978. The 30,000
lbs (15 tn) harvest in 2003 was a fraction of the 1978 harvest (Dohne
2004, as in petition).
The St. Lawrence River in Canada, one of the largest rivers in
North America, has seen little or no recruitment for the last 10 years,
with an estimate of only 1 percent of the stocks remaining in this
area. This observation is partially based on the age of eels (which
appear to be getting older, indicating a failure in recruitment) and
the monitoring of abundance at the eel ladder at the Moses-Saunders
Dam. Annual numbers of juvenile eels climbing the Moses-Saunders Dam
eel ladder decreased from a peak of 1,293,570 in 1983, to 935,170 in
1985, and went as low as 11,533 eels in 1992 (a 99 percent decline in
recruitment to Lake Ontario). Electrofishing surveys and waterfall
surveys of tributaries to the Gulf of St. Lawrence also point to an eel
recruitment decline between 1981 and 1985 of approximately 80-90
percent (Castonguay et al. 1994a). Lake Ontario scientific trawl
surveys from 1972-1999 (except 1989) indicated a downward trend with
catches in the last five years an order of magnitude lower than in the
first five years of the survey (ICES 2000). These observed declines may
have significant impacts on the eel rangewide, as the stock in the St.
Lawrence River is made up primarily of large spawning females. There is
concern that if their numbers are down, it may affect recruitment to
the entire Atlantic Coast. John Casselman, researcher for the Ontario
Ministry of Natural Resources, Canada, and others, hypothesize that a
substantial proportion of large female spawners for this panmictic
species are from the St. Lawrence system (ASMFC 2004). As a consequence
of the observed decline, the Ontario Ministry of Natural Resources
issued a moratorium in 2004 on commercial eel harvest for Ontario
waters, and a moratorium on recreational eel harvest is forthcoming
(Casselman pers. comm. 2005).
Recent information indicates that a decline in U.S. harvest
continues. Based on 2002 harvest reports collected by the ASMFC, the
long-term average (52 year period) for landings is down 64 percent, the
more recent average (past 20 years) for landings is down 44 percent,
and the most recent average (past 5 years) for landings is down about
30 percent (Geer 2004).
The information provided by the petitioners indicates that American
eel populations have generally declined and the species has lost much
of its habitat. Declines in eel populations appear to be most dramatic
in the Saint Lawrence, Lake Ontario, and northeastern states. In other
areas, such as the southeast, declines may not be as severe and
populations may be stable. Additionally, the American eel appears to
have lost the majority of its stream habitat, ranging from 91 to 77
percent habitat loss in states bordering the Atlantic Ocean. Although
much of the population trend information is based on harvest data
without any measure of effort, we believe that the petitioner has
provided substantial information indicating that the eel's population
has declined on a regional basis, in addition to experiencing severe
habitat loss.
Factors that may contribute to a possible population decline are
habitat loss and degradation, overharvest, disease, structures impeding
upstream and downstream passage, contaminants, and variable oceanic
conditions (further discussed in Discussion of Listing Factors).
Similar declines in the population of European and Japanese eels have
been observed (Moriarty and Dekker 1997, Tatsukawa and Matsumiya 1999,
as in Haro et al. 2000).
Discussion
In the following discussion, we respond to each of the major
assertions made in the petition, organized by the Act's listing
factors. Section 4 of the Act and its implementing regulations (50 CFR
424) set forth the procedures for adding species to the Federal list of
endangered and threatened species. A species may be determined to be an
endangered or threatened species due to one or more of the five factors
described in section 4(a)(1) of the Act. The five listing factors are:
(1) The present or threatened destruction, modification, or curtailment
of its habitat or range; (2) overutilization for commercial,
recreational, scientific, or educational purposes; (3) disease or
predation; (4) the inadequacy of existing regulatory mechanisms; and
(5) other natural or manmade factors affecting its continued existence.
The petition provided specific information on the life history of
the American eel, use of American eels by humans, population status,
obstacles to river passage, mortality by hydroelectric turbines, and
the impacts of contaminants, habitat loss, and harvest, as well as a
discussion of inadequacy of existing regulatory mechanisms.
Incorporated into the petition by reference was the ASMFC Interstate
Fishery Management Plan for American Eel (Management Plan) (ASMFC
2000), which summarizes peer reviewed papers on the status of the
species and recent and historical trends and
[[Page 38854]]
provides extensive information on the life history and the threats and
impacts affecting various life stages of the species, in the eastern
United States. Participating in the development of the Management Plan
were the Service; Maine Department of Marine Resources; New Jersey
Division of Fish; Game and Wildlife; Delaware Division of Fish and
Wildlife; South Carolina Department of Natural Resources; Maryland
Department of Natural Resources; and East Carolina University. This
document was also approved by the ASMFC board, which consists of
representatives from 15 Atlantic Coast States.
This 90-day finding is not a status assessment and does not
constitute a status review under the Act.
A. The Present or Threatened Destruction, Modification, or Curtailment
of Its Habitat or Range
The petition, its appendices, and referenced documents discuss the
following threats which we have grouped under Factor A: (1) Seaweed
harvest; (2) benthic habitat degradation; (3) alterations in stream
flow; (4) loss of wetland habitat; and (5) loss of upper tributary
habitat.
Seaweed Harvest
Information provided in the petition. The petitioner did not
provide specific information on the effects of seaweed harvest on
American eels. However, the Management Plan incorporated by reference
discussed seaweed harvest as a possible emerging threat to the ocean
spawning habitat.
Reproduction of all American eels occurs in the Sargasso Sea. One
species of Sargassum, a brown algae that is commonly found floating in
the Sargasso Sea and drifting along the Atlantic Coast from Florida to
Cape Cod, was harvested in U.S. waters primarily by one company. The
harvesting of Sargassum began in 1976, but has only occurred in the
Sargasso Sea since 1987 (ASMFC 2000).
Analysis of the information provided in the petition and
information in our files. The Management Plan proposes that the harvest
of Sargassum may affect American eels (ASMFC 2000). From 1976 through
1998, approximately 44,800 lbs (dry) of Sargassum have been harvested,
33,500 lbs of which were from the Sargasso Sea (ASMFC 1998). The ASMFC
stated that the harvesting of Sargassum was to be eliminated in the
South Atlantic Exclusive Economic Zone (EEZ) by January 2001; however,
a Management Unit for Sargassum was established in 2002 throughout the
South Atlantic EEZ and State Waters that did not eliminate harvest, but
instituted timing restrictions and established specific areas where
harvest is closed (ASMFC 2002). The remainder of the Sargasso Sea is
outside of the EEZ and currently not subject to restriction.
It is conceivable that harvesting Sargassum would affect eggs and
leptocephali, if harvest occurs where eggs and leptocephali are
present. There is also the potential that migrating or spawning adults
may be affected either directly or indirectly by the harvest of
Sargassum. We agree that seaweed harvest may impact American eels.
However, we are not aware of any analysis on the extent and impact of
this activity on the American eel; therefore, we are unable to speak to
whether seaweed harvest has caused or contributed to a decline in
American eel.
Benthic Habitat Degradation
Information provided in the petition. The petitioner did not
provide specific information on the effects of benthic habitat
destruction on American eels. However, the Management Plan incorporated
by reference discussed benthic habitat destruction as a possible threat
within the Continental shelf habitat.
The Management Plan also explained that larval migration, feeding,
and growth, and juvenile metamorphosis, migration, feeding, and growth
all occur on the Continental Shelf. Glass eel growth, distribution, and
abundance, according to the ASMFC, is probably impacted by a variety
direct effects (e.g., channel dredging and overboard spoil disposal)
and indirect effects (e.g., changes in salinity due to dredging) (ASMFC
2000).
Analysis of the information provided in the petition and
information in our files. Glass eels and elvers burrow or rest in deep
water during the day (Deelder 1958, as in ASMFC), and therefore may be
susceptible to activities, such as dredging, that disturb those
habitats. Channel dredging and overboard spoil disposal are common
throughout the Atlantic coast. Changes in salinity as a result of
dredging projects could alter the distribution of American eels.
Additionally, dredging associated with whelk and other fisheries may
damage benthic habitat for this species (ASMFC 2000). However, we are
not aware of any analysis on the extent and impact of these activities
on the American eel, and therefore, we are unable to speak to whether
benthic habitat degradation has caused or contributed to a decline in
the American eel.
Alterations of Stream Flow
Information provided by the petitioner. The petitioner did not
provide specific information on the effects that alterations of stream
flow have on American eels. However, the Management Plan incorporated
by reference discussed alterations of stream flow as being a possible
threat to their access to tributaries, which would limit upstream
recruitment.
Elvers are small (4 in/10 cm or less in length) and are poor
swimmers, initially utilizing tides when initiating upstream migration.
Elvers orient to river currents for their upstream migration (Tesch
1977, as in ASMFC 2000). Their upstream migration is a slow process
(Haro and Krueger 1988, as in Richkus and Whalen 1999, as in ASMFC,
estimated upstream migration rates of 6 m/day), and if the current
becomes too weak or too strong (changes in stream velocity), the eels
may move into backwater areas, severely delaying upstream progress
(Tesch 1977, as in ASMFC 2000). The onset of this active upstream
migration appears to be influenced by several environmental variables
(changes in water chemistry caused by intrusion of estuarine water, or
changes in pH or salinity), or other environmental variables such as
river current velocities, the odor of decomposing leaf detritus, or a
temperature threshold (Facey and Van Den Avyle 1987, Sorensen and
Bianchini 1986, as in ASMFC 2000).
Analysis of the information provided in the petition and
information in our files. Altering stream flows, such as rapid changes
in stream flow associated with hydroelectric project peaking operations
and water storage facilities, may limit upstream recruitment according
to ASMFC by affecting upstream migration (2000). However, we are not
aware of any analysis on the extent and impact of alterations of stream
flow on American eels, and therefore, we are unable to speak to whether
alterations of stream flow have caused or contributed to a decline in
the American eel.
Loss of Wetland Habitat
Information provided by the petitioner. The petitioner did not
provide specific information on the effects of wetland habitat loss on
American eels. However, the Management Plan incorporated by reference
discussed loss of wetland habitat under decreased availability of
important habitats.
Lost wetlands or access to wetlands have significantly decreased
the availability of important habitats for
[[Page 38855]]
feeding and growth of American eel juveniles and subadults (ASMFC
2000). Ackerknecht et al. (1984, as in ASMFC 2000) reported in 1984
that over half (54 percent) of the coastal wetlands in the lower 48
states have been destroyed.
Analysis of the information provided in the petition and
information in our files. Wetlands loss can be caused by filling and
dredging, and coastal subsidence. Degradation of wetland habitat has
occurred due to contaminants and the invasion of nonnative species.
Although prior losses have been significant, regulations implemented in
the 1970s have curbed declines by 42 percent. For example, all coastal
States in the lower 48, except Texas, have enacted special laws to
protect estuarine wetlands (Ackerknecht et al. 1984; Tiner 1991). The
ASMFC (2000) reported that the historic loss of wetland habitat, along
with loss of upper tributary habitat (discussed below), significantly
decreased the availability of important habitats for the feeding and
growth of American eels. However, the most significant loss of
estuarine wetlands occurred before the decline in the American eel was
reported. We agree that the loss of wetland habitat has likely impacted
and may continue to impact American eels. However, because of the
temporal discrepancy between the greatest wetland loss and the onset of
a decline, we believe that the loss of wetland habitat is unlikely the
single cause of the decline, but may have contributed to the decline in
combination with other factors.
Loss of Upper Tributary Habitat
Information provided by the petitioner. The petitioners presented
information on the decline of freshwater habitat available to American
eels, stating that it has declined, having been destroyed, modified, or
curtailed by at least 84 percent in the United States. This significant
loss of habitat is due to blockage or restriction caused by dams.
In a Busch et al. (1998, as in ASMFC 2000) assessment, they
determined that Atlantic coastal streams from Maine to Florida have
15,115 dams that can hinder or prevent upstream and downstream movement
of eels, resulting in a restriction or loss of access to 84 percent of
the stream habitat within the Atlantic Coastal historic range. This is
a potential reduction from 345,359 miles (556,801 kilometers) to 56,393
miles (90,755 kilometers) of stream habitat available for species such
as American eel. The greatest losses reported in Busch et al.'s study
were in the North Atlantic region from Maine to Connecticut where
potential habitat loss is estimated at 91 percent. The South Atlantic
region of North Carolina to Florida is estimated to have experienced a
77 percent loss of habitat (Busch et al. 1998, as in ASMFC 2000).
Although elvers will attempt to scale wetted substrates, such as small
dam faces, for many of the migrants, dams probably limit their ability
to pass these structures (Tesch 1977, as in ASMFC 2000).
In Canada, the construction of the Moses-Saunders Dam in 1954-58
impeded upstream (and downstream) migration on the St. Lawrence River,
restricting access by migratory fish from the Atlantic Ocean to Lake
Ontario and the Finger Lakes system in New York for 20 years. An eel
ladder, constructed at the dam in 1974, improved upstream passage
(ASMFC 2000).
Analysis of the information provided in the petition and
information in our files. Castonguay et al. (1994a) reviewed major
habitat modifications as a potential cause for the drastic decline of
American eels in the Lake Ontario and Gulf of St. Lawrence ecosystems.
Anthropogenic (human-caused) habitat modifications in the Lake Ontario/
St. Lawrence River ecosystem (such as the Moses-Saunders Dam) occurred
mostly before the 1960s, whereas the eel recruitment decline started
only in the early to mid 1980s. The lack of temporal correspondence
between permanent habitat modifications argues, according to Castonguay
et al. (1994a), against their role in the decline. However, they
provide caution to accepting this explanation, because of the American
eel's strikingly different life histories (panmictic, longer lived, and
ocean spawning as compared to anadromous fishes); catadromous fishes
(such as eel) are likely to respond more slowly to these anthropogenic
impacts compared with anadromous fish populations.
Although along the U.S. Atlantic Coast there remains some available
upstream habitat, unlike anadromous species such as herring or shad,
American eels have no particular homing instinct. The implication here
is that although rivers remain that allow for upstream migration, even
if an adult female successfully migrates down her resident stream and
spawns, the resulting young eels will not necessarily return to that
stream and could, due to currents, be delivered to an area with
upstream blockage. Returning to a stream with blockage does not
necessarily eliminate survival (as the young can remain in the lower
reaches and likely become male), but it may present increased risks of
predation (predation may be significant at the blockage where predatory
fish may congregate).
Based on the information provided by the petitioner and an analysis
of the information in our files, we agree with the petitioners'
assertion that the decline in American eel may be in some part
attributable to the loss of upper tributary habitat for female eel, and
if not responsible for the decline initially, may well be a limiting
factor as population numbers decrease.
B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Information provided by the petitioner. According to the
petitioners, it is undisputed that overutilization through harvest of
the American eel is occurring across the species' range in the United
States and that along with habitat loss, harvest pressure is a primary
cause of any possible historic and recent decline in abundance of the
American eel (Castonguay et al. 1994a and 1994b, as in ASMFC 2000).
The U.S. commercial fishery has traditionally supplied American
eels for the U.S. and European food markets, domestic trotline bait,
bait for domestic sport fisheries, and (at times) the Asian food
market. American eel fisheries exist in the United States, Canada, and
to a lesser extent the Caribbean and Central America. American eel
fisheries have fluctuated widely. For example, throughout the first
half of the 20th century, the eel fishery was small; however, as
European and Asian eel fisheries declined by the late 1960s, a strong
market developed in the early 1970's for live American glass eel and
elvers which range from 2-4 inches (Crawford 1996, as in ASMFC 2000).
Eastern Asia has an intensive aquaculture industry (165,347 tn/150,000
t metric production) which is dependent upon and supported by wild-
caught glass eel and elvers because artificial propagation of the
species from fertilized egg to commercial size has not been successful
(Moriarty and Dekker 1997, as in ASMFC 2000). Both glass and elver
commercial eel fisheries are scattered throughout the American eel's
range, with the present fishery concentrated in Maine (16,599 lbs
landed in 1995; ASMFC 2000).
Yellow eel spend from 2 to 30 years in fresh and estuarine habitats
before reaching sexual maturity and are harvested throughout that
period. According to ASMFC (2000) they are thus susceptible to
overharvest. Silver eels are sexually mature individuals and are
harvested in freshwater and marine environments throughout their range.
[[Page 38856]]
During strong market periods, for instance in the 1970s and 1990's,
legal shipment increases of over 153 and 230 percent, respectively,
were recorded (ASMFC 2000). Annual harvest reported in the mid 1970's
was in excess of 1,700 tons, and in the 1990's just under 14 tons.
These harvests are likely less than the actual amount exported as
underreporting has been an issue (underreporting has ranged from 3.6 to
261 percent) (ASMFC 2000). More recent information provided by the
petitioner indicates that U.S. landings on the Atlantic Coast are down
about 64 percent of the long-term average, possibly (Geer 2004).
Analysis of information provided in the petition and information in
our files. Information in our files provides additional detail on the
extent of the commercial and recreational American eel fishery. Few
recreational anglers directly target eel, but eel are often purchased
by recreational fishermen for use as bait for larger gamefish such as
striped bass. From the Atlantic coast area surveyed, the estimated
total annual catch of eel ranged from 212,690 eel in 1982 to 36,741 eel
in 1997 (ASMFC 2000). Some recreational fishermen may catch eels for
bait purposes directly, but not report such landings (ASMFC 2004).
Commercial exports of glass eels to Europe and Asia have led to
enforcement problems due to high prices, low cost of entry to the
fishery, and large numbers of participants. State agencies have focused
enforcement efforts on take while federal efforts have been focused on
foreign trade aspects of the fishery. A U.S. Fish and Wildlife Service,
Division of Law Enforcement (USFWS-DLE) review of foreign trade of
American eels from 1992 to 1996 revealed problems with reporting of
catches and exports, with records for 1993 showing more than twice as
many live American eels being exported as were reported caught in the
U.S. Commercial eel harvest is reportedly one of the largest commercial
fishing activities on the east coast due to the high economic
incentives associated with glass eels. The commercial ``on-the-street''
price for glass eels from the Atlantic seaboard ranges from
approximately $600 per pound in the early fishery to $100 per pound in
the late fishery (USFWS-DLE pers. comm.).
Illegal take of glass eels and possibly other life stages were not
recognized as a major problem until summer 1997. Numerous prosecutions
for illegal fishing activity involving glass eels have taken place in
state and federal courts since 1997. During the period March 1996
through March 1998, the Office of Law Enforcement expended a great deal
of man hours and effort focused on the protection of American eels.
This period saw a marked increase in illegal activity involving
American eels that was directly attributable to the black market value
of elvers. Service investigations revealed that during this period
poachers could easily expect to command in the neighborhood of $350 per
pound for eels, harvested at only about 2 to 4 inches long, that were
then exported live to Asia and Europe (USFWS-DLE pers. comm.).
In 1999 the Office of Law Enforcement observed a nearly complete
cessation of illegal activity involving American eels. This appears to
be the result of a bottoming out of the black market value for elvers
and not a reaction to previous enforcement activity. In 1999 commercial
fisherman, who could legally harvest elvers in Maine, reported they
were lucky to get $20-$22 a pound as compared to the $350 per pound
seen the year before. This drop in value apparently was the result of
the preference of Asian consumers for the taste of juvenile Asian eels
over American eels and the availability of farmed raised Asian eels.
During this three year period, the Office of Law Enforcement conducted
three separate but related investigations intended to detect and
prosecute subjects involved in illegal commercialization of elvers.
Current regulatory requirements make it difficult to document the
number of glass eels in the commercial trade. The Atlantic States
Marine Fisheries Commission has recommended that the Fish and Wildlife
Service proceed with listing the American eel in Appendix III of CITES
to allow for better monitoring of glass eel harvest and
commercialization. Recently the price for elvers has risen to $200 per
pound (USFWS-DLE pers. comm.).
Shifts in population makeup are evident in the upper Chesapeake Bay
in Maryland where harvest pressure is on larger eels. Weeder and Uphoff
(2003) noted a shift in population makeup between the 1980s and 1990s
toward younger, smaller eels being harvested. This is consistent with
responses to increased size selective fishing pressure (i.e. large eels
being exploited). Many exploited fish stocks decrease in size at
maturity as a compensatory response (Trippel 1995, as cited in Weeder
and Uphoff 2003). Harvest of large individuals unequally affects
females. Eels below 40 cm in length are either male or female, but
almost all eels greater than 40 cm are female. Additionally, suggests
Weeder and Uphoff, smaller eels may be less reproductively successful.
If there were sufficient reduction in the reproductive contribution
from particular areas, overall egg production would likely be impacted.
Because larval dispersal is random, a decline in larval production
would impact the entire species range, including those areas from which
the reproductive contribution of spawners was high. Weeder's more
recent work in association with Hammond (in review), stated that strong
fishing pressure, which removes thousands of pound of eels per day from
the small tidal estuaries they studied, is likely to cause reduced
densities consistent with the demographics they observed. Median catch-
per-unit effort (CPUE) of eels sampled in a fishery-independent survey
of Chesapeake Bay's Sassafras River, a heavily fished system, dropped
from 9 to 0 eels per eel pot (between 1981 and 1998) and median total
weight dropped from 2.5k kg/pot to 0 kg/pot. Conversely, an increase in
eel size was observed after fishing ceased in the Wye River. They
concluded that the lower fecundity and number of spawning adults may
reduce the amount of spawner biomass to unsafe levels.
Along with the commercial fishery in the U.S., an active commercial
fishery exists in Canada. Yellow and silver eel catches are reported
from the Lake Ontario/St. Lawrence River ecosystem as well as from the
Gulf of St. Lawrence and from Atlantic Nova Scotia and the Bay of Fundy
(ICES 2000). The mean annual catches of St. Lawrence River were 788 tn
(715 t) in 1984 and 592 tn (537 t) in 1991. The periodic reporting of
``river eel'' catches in the Caribbean and Central American countries
are believed to be glass eels/elvers caught for export. Information has
only been collected since 1975 and may very well be underreported. The
catches have ranged from 1.1 tn (1 t) (1975 in Mexico, 1988 and 1989 in
Dominican Republic, and 1989 in Cuba) to 54 tn (49 t) (Dominican
Republic in 1994) (ICES 2000).
In analyzing the effect of harvest on American eel abundance, there
are various reasons the magnitude of the threat is difficult to
determine. Most of the data on eel numbers come from commercial harvest
data (or landings) where fishing effort is not always available and may
consist of different year-classes which are not differentiable simply
based on eel size (ASMFC 2000). Harvest is market driven and therefore
high harvest years may reflect high market demand rather than increased
abundance (likewise, low harvest numbers may indicate a low market
demand rather than a decrease in abundance). Harvest of highly valued
[[Page 38857]]
glass eels or elvers to meet foreign aquaculture demands are likely
underreported, and there is evidence of substantial illegal harvest and
sale of glass eels and elvers having occurred through the 1990s on the
Atlantic Coast (R. St. Pierre, pers. comm. 2005).
The absence of fishing effort information was identified by
Castonguay et al. (1994a) as a major weakness in their assessment of
commercial fishing and declines in the American eel. They analyzed
trends in commercial eel landings in Canada and the United States and
compared them to the timing of the decline. They concluded that there
was little evidence that commercial fishing caused the decline.
Ongoing research by Chesapeake Bay area scientists, however,
suggests that eels appear to be overfished. Fishing mortality has been
estimated at two to four times natural mortality (Weeder, J. and J.
Uphoff. In in review). Although this does not point to the reason for
the decline, it may indicate, at least in the Chesapeake Bay, an
important area for American eels, current fishing pressure may be
affecting future abundance.
There are several factors occurring on, and affecting the abundance
of, multiple life stages (glass, elver, yellow, and silver) of American
eel. These factors increase the risk that significant harvest pressure
poses for the American eel population due to their life history.
According to the ASMFC (2000), the following factors should be
considered in any analysis of harvest effects: (1) American eels mature
slowly, requiring 7 to 30+ years to attain sexual maturity (K.
Oliveira, Univ. of Maine pers. comm., as in ASMFC 2000); (2) glass eels
aggregate seasonally to migrate, making them more vulnerable to capture
in large numbers (Haro and Krueger 1988, as in ASMFC 2000); (3) one
year class of yellow eels are harvested over many years, resulting in
high cumulative fishing mortality (Richkus and Whalen 1999, as in ASMFC
2000); (4) all harvest is pre-spawning (McCleave 1996, as in ASMFC
2000); and (5) changes in year class abundance are not readily
recognizable, because harvest abundance data include eels of similar
sizes but from a number of year classes (Ritter et al. 1997, as in
ASMFC 2000), potentially masking declines.
In responding to the petitioners' assertion that commercial harvest
is a threat to the American eel we were presented with differing
analyses on whether and to what degree legal and illegal harvest is
implicated in the decline, and complicating factors in determining
harvest impacts. As part of our 12-month status review of the American
eel, we will determine the implications of these factors on the role of
harvest on the eel's decline. Information from the Chesapeake studies
suggests that not only numbers, but eel size may well be important in
determining the impacts of harvest, as have already been noted in the
Chesapeake Bay. Because the petitioner and the ASMFC indicated that
commercial harvest is a possible reason for the decline of the American
eel and that at the 90-day finding stage we accept the petitioner's
sources and characterizations of the information, to the extent that
they appear to be based on accepted scientific principles, we conclude
that commercial harvest likely effects American eel abundance, although
it may not be solely responsible for its decline, and we conclude that
commercial harvest is likely to impact the American eel in the future.
C. Disease or Predation
Information provided in the petition: The petition did not
specifically provide information on disease and predation: however, the
Management Plan incorporated by reference provided the information
below.
Disease
American eels are afflicted by disease like any other species;
however, one disease was specifically discussed by ASMFC as a potential
threat to the overall health of the American eel. The non-indigenous
eel swimbladder nematode (Anguillicola crassus) is a parasite native to
marine and freshwater areas of eastern Asia, from Japan and China to
Vietnam. Its native host is the Japanese eel (Anguilla japonica). The
nematode has been documented to have significant negative impacts on
European eels, and on American eels in Texas and South Carolina.
Analysis of information provided in the petition and information in
our files. The swimbladder nematode was found in American eels (Barse
and Secor 1999, as in ICES 2000) in 1997, but may have been present
earlier. The nematode has been implicated with acute mortality in eels,
as well as internal injury and growth impairment. Part of its life
cycle occurs in the eel's swim bladder, and its departure through the
swim bladder wall can cause injury and scarring. These effects on the
swim bladder could impact a silver eel's ability to travel to the
Sargasso Sea spawning grounds and thus its reproductive success (ICES
2000).
Although there is evidence that the parasite Anguillicola crassus
causes negative impacts to Anguilla spp, according to the International
Council for the Exploration of the Sea (ICES) (2000), it is unlikely
that there are substantial effects from the parasite on American eel
abundance (because of the lack of temporal correspondence between the
appearance of the parasite and American eel declines).
Predation
American eel juveniles and adults are a seasonal food item of
various finfish, and data are available that indicate eels are preyed
on by fish-eating birds and mammals such as mink (Sinha and Jones 1967,
Seymour 1974, as in ASMFC 2000). Younger life stages may also provide a
food source.
Analysis of information provided in the petition and information in
our files. Under conditions of abundance, impacts from predation would
not be of concern; however, when populations are declining, or
particular life stages are experiencing heavy predation, the impact of
what were typical stresses may be magnified. The information provided
and available in our files is, however, insufficient to determine the
role of predation in the decline of the American eel.
D. The Inadequacy of Existing Regulatory Mechanisms
The petition stated that State and Federal agencies have not
adequately regulated (1) fish passage, or (2) harvest and trade,
leading to a decline in population numbers and range of the American
eel.
Fish Passage
Information provided by the petitioner. The petitioners stated that
under the authority of the Federal Power Act, the Federal Energy
Regulatory Commission (FERC) can immediately stop the killing of adult
female American eels in hydroelectric turbines in the United States,
but have failed to do so. They also state that the Service and NOAA
Fisheries, pursuant to Section 18 of the Federal Power Act, have the
legal authority to require the licensees of private hydroelectric dams
to provide safe and efficient upstream and downstream passage for
American eels. The petitioners allege that, to date, neither agency has
exercised this legal authority. Additionally, the petitioners state
that pursuant to the Federal Clean Water Act, the Environmental
Protection Agency (EPA) has the legal authority to require the
licensees of private hydroelectric dams to provide safe and efficient
upstream and downstream passage for American eels. Allegedly, to date,
the EPA has declined to exercise this legal authority. Finally,
[[Page 38858]]
the petitioners were not aware of any instance in Maine or
Massachusetts where these States have required by law the safe and
efficient passage of American eels at non-hydroelectric dams, despite
fish passage statutes which allow the States to make such requirements.
Also, the petitioners questioned whether other States had statutes
requiring safe and efficient passage of juvenile American eels at non-
hydroelectric dams and whether such statutes were being enforced.
Analysis of information provided in the petition and information in
our files. Safe upstream and downstream passage, which the petitioner
alleges lacks adequate regulatory mechanisms, is standard when special
licenses are required. For example, dams for hydropower production and
navigation provide opportunities for fish passage when required by the
resource management agencies, such as the Service. The Service takes
every opportunity available to insure that safe upstream and downstream
passage is prescribed for American eels under the Federal Power Act
during relicensing of hydroelectric power facilities that are under the
purview of FERC. NOAA Fisheries has exercised its legal authority under
the Federal Power Act to prescribe fishways for eels at select
projects. However, not all hydroelectric power facilities are currently
equipped with structures that ensure safe upstream and downstream
passage. Of the 15,570 dams on the Atlantic Coast only 1,100 dams were
identified for hydropower production and 50 for navigation. Therefore,
over 90 percent of the dams in the range of the American eel, including
those for water-level control, water supply, and recreation, do not
necessarily have Federal licensing requirements (ASMFC 2000), but not
all these structures would be considered barriers.
To the extent that we find safe upstream passage (Factor A. Access
to upper tributary habitat) and downstream passage (Factor E.
Hydropower turbines) may be responsible in part for the decline of the
American eel, we concur with the petitioners that the existing
regulations for facilities preventing safe up and downstream passage
may be inadequate or not exist because the vast majority of these dams
do not have Federal licensing requirement, and therefore, may be partly
responsible for the decline of the American eel.
Harvest and Trade
Information provided by the petitioner. The petitioners stated that
under the authority of the Magnuson-Stevens Fisheries Conservation and
Management Act, the ASMFC can immediately prohibit the harvest of
American eels in the waters of the United States from Maine to Florida,
and asserted that they have not exercised this authority.
Analysis of information provided in the petition and information in
our files. The Magnuson Stevens Fisheries Conservation and Management
Act does not apply as indicated by the petitioner. The Atlantic Coastal
Fisheries Cooperative Management Act does allow for emergency actions
to be taken by the ASMFC and obligates States to implement the
emergency actions (e.g., harvest restrictions). To address concerns
regarding coastwide declines in American eel abundance, the ASMFC's
American Eel Management Board authorized development in March 2004, of
an Amendment to the Interstate Fishery Management Plan for American
eel, which may include changes in harvest restrictions for recreational
and commercial fisheries. However, these are not currently in place,
and a large number of eel use areas/habitats are outside the
jurisdictional boundaries of the State agencies within the purview of
the ASMFC. These include watersheds in the Canadian Atlantic Provinces
of Quebec and Ontario, upstream freshwater reaches managed by inland
fish and wildlife agencies, regional institutions such as the Gulf
States Marine Fisheries Commission and Great Lakes Fishery Commission,
and those waters within Native American Reservations where Tribal
Governments have jurisdiction. To date, of these other jurisdictions,
only the Province of Ontario, Canada, has placed a moratorium on the
harvest of American eels.
Currently, Atlantic Coast states differ in their eel harvest
regulations, such as variations in the minimum size of harvestable eel,
dates of harvest, and fishing gear. Few states have defined fishing
seasons and limited management over the eel fishery (ASMFC 2000).
The ASMFC also recommended in the Management Plan that the
Secretary of Commerce address and initiate controls over harvest and
use of American eels in Federal waters (3-200 nautical miles offshore)
that are not landed in States' waters. Specifically, the ASMFC
recommended that the Secretary of Commerce ban harvests of American
eels at any life stage in the EEZ, but permit the possession of up to
50 eel per person as bait. NOAA Fisheries does not now have a fishery
management plan for eels and does not manage the fishery in the EEZ.
In summary, although individual jurisdictions have taken some
action in response to the decline of the American eel (Canada's
moratorium on commercial harvest in Ontario) or are considering changes
(ASMFC Amendment 1), there are both gaps in the ability of current
regulations to address threats (varied state regulations), and as the
petitioners pointed out, limited implementation of existing regulatory
mechanisms (limited and varying state restrictions on eel harvest,
harvest within the EEZ). To the extent we find that commercial harvest
(Factor B. Overutilization for commercial, recreational, scientific, or
educational purposes) may be responsible in part for the decline of the
American eel, the existing regulations may be inadequate or nonexistent
and therefore partly responsible for the decline of the American eel.
E. Other Natural or Manmade Factors Affecting Continued Existence
The petition, its appendices, and referenced documents discuss the
following threats which we have grouped under Factor E: (1) Hydropower
turbines; (2) displacement by or competition with nonnative species:
(3) contaminants; and (4) changes in oceanographic conditions.
Hydropower Turbines
Information provided by the petitioners. According to the
petitioners, radio tagging studies of migrating female American eels
conducted by the Maine Department of Marine Resources (MDMR) at two
hydroelectric dams in Maine indicate nearly 100 percent of adult female
eels entering project turbines are killed or severely injured, and
therefore unable to complete their spawning migration (MDMR 2002, as in
petition). Additionally, the Petitioner's state, ``Radio-tracking of
adult American eels by Maine Department of Marine Resources just above
the Lockwood hydro-electoric project on the Kennebec River during fall
2002 indicates that 40 percent or more of the adult American eel
attempting to migrate past the Lockwood Project each fall are entrained
and killed in the Lockwood Dam turbines, despite the availability of
the project spillway for passage (MDMR 2003). According to the
petitioner, the entrainment and death of eels in the turbine is not a
recent issue. The petitioners' state that records of severe kills of
female American eels by the turbines of hydro-mechanical and
hydroelectric dams exist since as early as the 1880s.
Downstream passage of silver eels is stated by ASMFC (2000) as a
problem in
[[Page 38859]]
streams with hydropower turbines. According to Ritter et al. (1997, as
in ASMFC), the 1,100 hydropower dams on the eastern seaboard of the
United States may represent a major source of mortality to pre-spawning
adults and represent approximately 7 percent of the dams on the eastern
seaboard. According to the petitioners, virtually none of these
hydropower facilities provide safe passage for migrating female
American eels. As a result, downstream passage by female American eels
at these facilities is via the project turbines, which results in the
death of female eels attempting to migrate. According to Hadderingh
(1990, as in ASMFC) and McCleave (pers. comm., as in ASMFC), if eels
have to pass through turbines in their downstream migration, mortality
rates range from 5 to 60 percent depending on the flow through the
turbines and the length of the individual.
Analysis of information provided in the petition and information in
our files. We agree with the petitioners' assertions that rivers with
hydropower turbines are a documented threat to female American eels as
they leave the rivers to spawn and may be a threat to the species as a
whole. Although hydropower turbines are on less than 7 percent of the
rivers, this mortality may be playing a larger role as the population
declines (because as the population declines, gravid females become a
vital resource and a high percentage of these individuals are lost to
hydropower turbines). Additionally, not all hydroelectric power
facilities are currently equipped with structures that ensure safe
upstream and downstream passage. There is particular concern that the
St. Lawrence River/Lake Ontario stock, a significant (possibly 19
percent of total female spawners) source of old, large, fecund female
spawners (Castonguay et al. 1994a), is impacted by turbines at the
Moses-Saunders and Beauhrnois-Les C[eacute]dres hydroelectric complex
on the St. Lawrence River.
Displacement by or Competition With Nonnative Species
Information provided by the petitioners. The petitioner did not
provide information on the impact of displacement by or competition
with nonnative species. Rather, what is presented below is recent
information from a petition reference on a potentially emerging threat.
Two nonnative species may be impacting American eels, the flathead
catfish (Pylodictis olivaris) and the blue catfish (Ictalurus
furcatus), both native to the Mississippi River watershed. These two
species, according to the minutes from the 2004 ASMFC meeting, have
exploded in certain areas, having been introduced as recently as the
early 1980s in some systems. They have displaced some of the indigenous
catfish species. There has been speculation from some research done at
Virginia Commonwealth University that they have a large impact on the
shad population and potentially on the American eel population as well
(ASMFC 2004). Because no additional information was presented or
available in our files at this time, we are unable to analyze further
the impact of displacement by or competition with nonnative species on
American eels.
Contaminants
Information provided by the petitioners. As the petitioners state,
American eels are benthic, long-lived, and lipid (fat) rich
(bioaccumulation of many toxins occurs in the fat of the fish).
Therefore, American eels can accumulate high concentrations of
contaminants, potentially causing an increased incidence of disease and
reproductive impairment than is found in other fish species (Couillard
et al. 1997, as in ASMFC). Studies have shown bioaccumulation of
mercury and other heavy metals, dioxin and chlordane, polychlorinated
biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in American
eels.
An analysis of the contaminants in migrating silver eels in the St.
Lawrence River showed that the highest concentrations of chemicals were
in the gonads. Concentrations of PCB and DDT were found to be 17
percent and 28 percent higher in the gonads than in the carcasses. The
chemical levels in the eggs could exceed the thresholds of toxicity for
larvae. Also, since the migrating females are not feeding, the chemical
levels in the eggs could be even higher at hatching, increasing the
likelihood of toxicity to the larvae (Hodson et al. 1994, as in ASMFC
2000). According to ASMFC (2000), in the St. Lawrence River migrating
silver eels, vertebral malformations and basophilic foci (lesions) in
the liver were found to be most common in contaminated eels (Couillard
et al. 1997, as in ASMFC 2000).
Aside from bioaccumulation, ASMFC expressed concern over accidental
spills and mosquito abatement practices and their effect on eels.
Accidental release of toxins into the Rhine River in 1986 killed
hundreds of thousands of European eels (Facey and Van Den Avyle 1987,
as in ASMFC 2000). Toxicity studies of aquaculture chemical effects on
various life stages of the American eel suggest increased tolerance
with size and age (Hinton and Eversole 1978, 1979, 1980, as in ASMFC
2000). A relatively new, specific area of concern deals with coastal
wetlands and the potential impact caused by spraying insecticides for
mosquito control at the time glass eels enter these areas (ASMFC 2000).
Analysis of information provided in the petition and information in
our files. Contaminants clearly accumulate in American eels at high
levels. Some evidence indicates that contaminant levels may be high
enough to be toxic to larvae and possibly affect the health of adult
migrating eels. However, we were not presented with information, nor
did we have information in our files, on the level of risk to the
species from different contaminants. Declines in recruitment in the St.
Lawrence River (and in Europe), according to Castonguay et al., do not
coincide with periods of maximum contamination by organochlorine
compounds (Castonguay et al. 1994a; Knights 1996, as in ICES 2000), and
ICES stated that spawners would still be available from uncontaminated
areas (ICES 2000). Therefore, in responding to the petitioners'
assertion that contaminants are a threat to the American eel, we can
agree that individual American eel and their young are likely at risk
from certain contaminants: however, the petitioners did not provide
substantial information nor do we have any in our files supporting this
assertion. Therefore we are unable to support, at this time, the
assertion that contaminants are a threat to the species at a population
level.
Changes in Oceanographic Conditions
Information provided by the petitioner. The petition did not
specifically provide information on the effects that changes in
oceanographic conditions are having on American eel abundance and
distribution, but the Management Plan incorporated by reference
provided the information below.
The ASMFC lists changes in oceanographic conditions as a concern to
the ocean habitat of the American eel. The spatial and temporal
distribution of leptocephali is a result of oceanic circulation
patterns and the drifting behavior of the larvae, and therefore
potential changes in oceanographic conditions that influence the
transport of leptocephali may have an impact on juvenile recruitment to
coastal tributaries, potentially impacting an overall year class
(McCleave 1998; Castonguay et al. 1994b, as in ASMFC 2000). Castonguay
et al. (1994a, as in
[[Page 38860]]
ASMFC 2000) suggests that a weak, slow Gulf Stream would cause larvae
to miss the optimum period for metamorphosis and be lost to the
population. Castonguay et al. (1994a, as in ASMFC 2000) also suggests
that recent cooling events and oceanographic changes in the northwest
Atlantic may have altered the currents or other processes that carry
glass eel to the continent.
Analysis of information provided in the petition and information in
our files. Eels are expected to be even more affected by North Atlantic
climatic changes than most marine species as the relative strength and
position of the Gulf Stream is vital for their dispersal and successful
migration, and the species consists of a single spawning population
which may depend on the strength or location of thermal ocean fronts to
trigger spawning. Evidence of historic population contractions is
presented for both the American eel and the European eel. Most of these
events probably occurred during the Wisconsinan glaciation 20,000 years
ago, which changed ocean circulation, thereby reducing the speed of the
Gulf Stream (Duplessy 1999, Lynch-Stieglitz et al. 1999, as in Wirth
and Bernatchez 2003), and moved the gyre boundary and associated
currents further to the south (Keffer et al. 1988, as in Wirth and
Bernatchez 2003).
However, the degree to which recent (within the last 30-40 years)
oceanic changes have contributed to the American eel population decline
is still being debated. Castonguay et al. (1994a) evaluated the role of
oceanic variations in the decline of both the American and European
eel, and although they could not test the hypothesis of reduced
recruitment directly, they found the most important result of their
analysis to be the similarity between North America and Europe in both
the rate of decline of these two eel species and the year in which the
decline began. That such declines could be due to simultaneous and
equivalent habitat, pollution, or fishing pressures, they say, is
unlikely. Rather they conclude that the most probable cause is an
oceanic factor acting simultaneously on both species.
We would concur with the ASMFC that changes in oceanographic
conditions (i.e. changes in the strength and direction of ocean
currents `` in particular the Gulf Stream) may have an impact on
juvenile recruitment to coastal tributaries, particularly those on the
Atlantic seaboard. Also, because of the lack of information in our
files to the contrary, we concur that changes in oceanic conditions may
be a reason for a decline in the American eel abundance and their
distribution, whether taken singly or in combination with other factors
discussed above.
Summary
It is reasonable to infer, as the petitioners proposed and
scientifically supported, that the American eel is experiencing a
decline. The petitioner also provided information on possible reasons
for this decline which are generally not refuted, but more often are
validated by the information in our files, which suggests that the
listing action may be warranted. Our review of the ASMFC 2000
Management Plan (which the petitioner incorporated by reference and
which the Service and NOAA Fisheries, State representatives, and
academics were involved with writing), with regards to the life history
of the species, potential threats to the various life stages of this
species, and the habitats it utilizes, provided us with a range of
potential causes for the decline and the likely effects to the species.
These potential threats and effects provided by the petitioner were
supported by scientific research with gaps in information acknowledged.
The complex life history and the incompleteness of historical data
(abundance, stock composition, life stage mortality rates, and
exploitation rates) make it challenging at this time to understand the
potential influence of the numerous individual threats, and threats
acting in a cumulative fashion or synergistically. Individual and
cumulative effects of these threats upon the American eel may be
magnified as the species' abundance declines, and as proposed by Wirth
and Bernatchez (2003), there may be a synergistic effect of the short-
and long-term threats faced by the species because of its peculiar life
history.
Further analysis of oceanic variations is necessary particularly in
light of the scant direct evidence and the potential for oceanic
variations to be compounding or confounding the impact of other
threats. Commercial harvest, habitat loss and degradation (primarily
the loss of wetlands and upper tributary habitat), hydropower turbine
mortality, and inadequacy of existing regulatory mechanisms, may also
have caused or contributed to the decline of the American eel. Other
potential threats, such as seaweed harvest, benthic habitat
destruction, alterations of stream flow, disease, predation, and
contaminants, could not be fully addressed or supported.
Finding
On the basis of our review, we find that the petition presents
substantial scientific and commercial information indicating that
listing the American eel may be warranted. The main threats to the
species presented by the petitioner and supported by the information
they provided appear to be commercial harvest, habitat loss and
degradation due to loss of wetlands and upper tributary habitat,
hydropower turbine mortality, changes in oceanic conditions, and
inadequacy of existing regulatory mechanisms.
Public Information Solicited
When we make a finding that substantial information is presented to
indicate that listing a species may be warranted, we are required to
promptly commence a review of the status of the species. To ensure that
the status review is complete and based on the best available
scientific and commercial data, we are soliciting information on the
American eel. We request any additional data, comments, and suggestions
from the public, other concerned governmental agencies, Native American
Tribes, the scientific community, industry, or any other interested
parties concerning the status of the American eel. We are seeking
information regarding the species' historical and current status and
distribution, its biology and ecology, ongoing conservation measures
for the species and its habitat, and threats to the species and its
habitat.
Finally, if we determine that listing the American eel is
warranted, it is our intent to propose critical habitat to the maximum
extent prudent and determinable at the time we would propose to list
the species. Therefore, we request data and information on what may
constitute physical or biological features essential to the
conservation of the species, where these features are currently found
and whether any of these areas are in need of special management, and
whether there are areas not containing these features which might of
themselves be essential to the conservation of the species. Please
provide specific comments as to what, if any, critical habitat should
be proposed for designation, if the species is proposed for listing and
why that proposed habitat meets the requirements of the Act.
If you wish to comment or provide information, you may submit your
comments and materials concerning this finding to the Division of
Endangered Species (see ADDRESSES section).
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Our practice is to make comments and materials provided, including
names and home addresses of respondents, available for public review
during regular business hours. Respondents may request that we withhold
a respondent's identity, to the extent allowable by law. If you wish us
to withhold your name or address, you must state this request
prominently at the beginning of your submission. However, we will not
consider anonymous comments. To the extent consistent with applicable
law, we will make all submissions from organizations or businesses, and
from individuals identifying themselves as representatives or officials
of organizations or businesses, available for public inspection in
their entirety. Comments and materials received will be available for
public inspection, by appointment, during normal business hours at the
address listed above under ADDRESSES.
Literature Cited
A complete list of all references cited herein is available, upon
request, from the Hadley, Massachusetts, Regional Office (see ADDRESSES
section above).
Author
The primary author of this notice is Heather Bell, Hadley,
Massachusetts, Regional Office (see ADDRESSES section above).
Authority: The authority for this action is the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: June 21, 2005.
Matt Hogan,
Acting Director, Fish and Wildlife Service.
[FR Doc. 05-12971 Filed 7-5-05; 8:45 am]
BILLING CODE 4310-55-P